The alarming stat is that 21% of American adults are functionally illiterate, meaning they unable to complete basic reading tasks.

Over half of the adults read below sixth grade level.

About 130 million U.S. adults (54% of those aged 16–74) read below a sixth-grade level, according to modeled estimates.

https://www.nu.edu/blog/49-adult-literacy-statistics-and-facts/

We actively teach kids to pattern match and “guess” what the other words are from the ones they recognize.

Unless you're talking about something totally different, that just sounds like using roots and context clues – a normal, healthy, and constructive way of understanding language.

We actively teach kids to pattern match and "guess" what the other words are from the ones they recognize.

Yes, I call that learning to read. Upside down and without vision correction, sometimes, because you are pretending to be someone without glasses, this is a profoundly useful skill. But also yes, just learning to read is you know, good.